Pedal units for bicycles of the known art comprise a central movement associated with a tube of the bicycle frame and two pedal cranks fixed to opposite ends of the central movement.
The central movement substantially comprises a pin disposed horizontally perpendicular to the bicycle travel direction, and bearings positioned at the ends of the pin to enable the connection to the bicycle frame.
The pedal cranks are mounted on the central movement such as to lie in a single plane, at least with reference to a leading extending axis of the pedal cranks.
A pair of pedals are mounted on the pedal crank in opposite positions about the central movement.
Disadvantageously, the pedal stroke with this traditional configuration of the pedal cranks presents so-called dead points, i.e. angular positions of said pedal cranks in which the pedals are at a maximum and a minimum level. In these positions, the action of the user in the vertical direction on the pedals is substantially aligned with the pedal crank and the torque applied thereto is consequently zero. Hence to overcome the dead angle positions, the user has to apply a direct additional action perpendicular to the pedal crank.
This renders the pedal stroke uncomfortable and awkward.